Field of the Invention
This invention generally relates to a bicycle freewheel. More specifically, the present invention relates to a bicycle freewheel that is configured to reduce freewheeling noise.
Background Information
In some bicycles with multiple speeds, a wheel of the bicycle, typically the rear wheel, is provided with a bicycle freewheel that is arranged on a hub of the wheel. The bicycle freewheel usually has a one-way clutch function whereby it only transfers torque in one direction. Thus, freewheels are used so that the bicycle can advance freely without any rotation of the pedals (i.e., during coasting). During coasting, the bicycle freewheel is considered to be in a state of freewheeling in which the bicycle wheel can freely rotate while the sprockets remain stationary.
One well-known conventional type of bicycle freewheel is provided with a pawl-type one-way clutch that includes ratchet teeth and clutch pawl configured to mesh with the ratchet teeth. In pawl-type one-way clutches, the clutch pawls are forced (spring loaded) toward engaging positions where they mesh with the ratchet teeth. During freewheeling, the bicycle freewheel often makes a freewheeling noise. Several attempts have been made to produce bicycle freewheels that are configured to reduce the freewheeling noise. Examples such types of bicycle freewheels are disclosed in U.S. Pat. Nos. 6,202,813; 7,617,920; and 7,938,242. In these patents, the bicycle freewheels are configured to prevent a pawl member from contacting with a ratchet-tooth member during freewheeling. However, these freewheels use a structure that retracts the pawl member during freewheeling. Thus, these bicycle freewheels are relatively more complex than conventional bicycle freewheels.